The present invention generally relates to electronic devices capable of employing expansion cards which provide specialized functions or resources to the device, or which extend the devices"" ability to communicate with and/or control peripheral devices, networks, or the like. In particular, the present invention relates to an electronic device having a chassis including a card hold down assembly for retaining or securing expansion cards within the chassis.
Electronic devices, particularly computer systems, servers, photocopiers, facsimile machines, printers, control equipment, medical equipment, telecommunication equipment, and the like often include one or more expansion cards which provide specialized functions or resources to the device, or which extend the devices"" ability to communicate with and/or control peripheral devices, networks or the like. Such expansion cards typically comprise generally rectangular printed circuit boards having an edge connector formed along one side edge. The edge connector is inserted into an expansion slot disposed on a system board (often referred to in the art as a motherboard) mounted within the electronic device to couple the installed expansion card to other electronic components in the device. In typical configurations, the expansion slots are oriented so the expansion cards installed therein are arranged in a spaced apart, generally parallel array wherein end edges of the cards are aligned with each other.
Extending along the aligned end edges of the expansion cards are metal mounting brackets having outwardly bent tabs positioned adjacent to the side edges of the cards opposite the edge connector. When the expansion cards are installed within the chassis of the electronic device and seated in the expansion slot, these tabs rest against a ledge surface formed inside the chassis. Notches disposed in the tabs overlie and register with holes formed in the ledge surface allowing the mounting bracket to be secured to the surface by a screw or bolt extending through the tab notch and threaded into the hole.
Because fasteners such as a screws or bolts are used to secure the mounting bracket tabs to the ledge surface, installation and removal of expansion cards is somewhat difficult and time consuming, and requires the use of tools such as a screwdriver or wrench. As a result, it would be advantageous to eliminate the fastener, relying on the expansion slot itself to hold the expansion card in place. However, electronic devices, particularly personal computers, are often subjected to substantial shock and vibration during delivery from the manufacturer to a retailer or the consumer. If not retained therein by the fastener, this shock and vibration could cause expansion cards to become unseated from their expansion slots on the system board causing the expansion card to not function properly.
Known to the art are card retaining assemblies that employ a clamp to hold each expansion card in place. These clamps are hinged to the back panel of the computer""s chassis so that they pivot through a hole formed in the back panel to hold the mounting bracket tab against the ledge surface. However, because the clamps, which are typically formed of plastic because of their complex shape, must pivot through a hole in the back panel, it becomes very difficult to provide adequate shielding against electromagnetic interference since the hole cannot be completely covered. Further, because a separate clamp is required for each expansion slot, such card retaining assemblies are relatively complex and costly to manufacture. Finally, such card retaining assemblies do not provide a means of securing the expansion card during shipping or movement of the computer system.
Consequently, it would be advantageous to provide an electronic device having a case or housing comprising apparatus for securing expansion cards within the chassis of an electronic device and allowing quick removal and installation of expansion cards without the need for individual fasteners to hold each card in place. Such a card hold down apparatus should be simple to manufacture, should provide good EMI shielding to the electronic device, and should be capable of retaining multiple expansion cards if so configured.
Accordingly, the present invention is directed to a card hold down assembly for retaining one or more expansion cards within the chassis of an electronic device such as a computer system, server, photocopier, facsimile machine, printer, or the like. In an exemplary embodiment, the chassis of an electronic device includes an aperture through which the securing tab of an expansion card may extend when the expansion card is inserted within an expansion slot and a tab retaining surface extending from said chassis against which the securing tab may rest when extended through the aperture. A retainer is removably attachable to the chassis for engaging the tab retaining surface to at least partially restrain the securing tab against the tab retaining surface for securing the expansion card in the chassis. A fastener secures the retainer to the tab retaining surface.
It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.
The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:
FIG. 1 is a partial isometric view illustrating a computer chassis including a card hold down assembly in accordance with an exemplary embodiment of the present invention;
FIG. 2 is a partial isometric view of the computer chassis illustrated in FIG. 1, wherein retainer of the card hold down assembly is removed from the chassis;
FIG. 3 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating expansion cards seated within expansion slots of a system board of the computer and retained within the chassis by the card hold down assembly; and
FIG. 4 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating removal of an expansion card from the computer.
FIG. 5 is a partial isometric view of the computer chassis shown in FIG. 1, further illustrating an expansion port cover for covering expansion ports of the chassis; and
FIGS. 6 and 7 are partial cross-sectional views of the card hold down assembly of the computer chassis shown in FIG. 1, wherein the retainer is shown attached to the chassis in FIG. 6 and removed from the chassis in FIG. 7.